Warning: even more pic heavy than usual.
Note: This review is an update from my previous review of the pre-release samples of the BK-FA01 and BK-FA02. Please continue all conversations in this thread, thanks!
As mentioned above, I recently reviewed the pre-release versions of the Niwalker Black Light Vostro series of 4x18650 lights – the BK-FA01 (XM-L2) and BK-FA02 (MT-G2). Niwalker has sent me the final shipping versions, which I will review in detail here. As you will see, there have been a few changes – due in part to my recommendations on the pre-release samples.
With the final release, Niwalker has provided more detailed specs for this series.
Manufacturer Reported Specifications:
(note: as always, these are simply what the manufacturer provides – scroll down to see my actual testing results).
- Working voltage 8.4V - 13V
- Integrated cool fins design provide better cooling
- Smooth polished reflector creates maximum throw
- Aircraft grade aluminum, mil-spec hard anodized for maximum wear
- Toughened ultra-clear tempered glass lens with anti-reflective coating
- Large cooper heat sink pad for superior thermal conductivity
- Magnetic ring control switch allows you to select desired output easily
- Twist the front magnetic ring in clockwise direction for Strobe, Off, L1, L2, L3, L4, L5, and L6 mode
- Uses four 18650 batteries for extended period runtime (able to use 2 or 3 18650s if needed) or 4, 6, and 8 CR123 primary batteries.
- Battery holder can be loaded into searchlight either way
- Low voltage warning to alert user to recharge batteries in time (output drops to L2)
- Impact resistant to 1.5m
- IPX-8, 2m (waterproof and submersible)
- LED: Cree XM-L2 U2
- ANSI FL-1 Output/Runtime: 1280 lumens (1hr 54min), 975 lumens (2hr 19min), 600 lumens (3hr 53min), 148 lumens (17hr 43min), 38 lumens (4.5 days), 3 lumens (40 days)
- 142,000 cd beam intensity / 755m beam distance
- Constant current circuit design offers constant output
- Total length: 208.5mm / Light body diameter: 51mm / Light head diameter: 80mm
- Weight 678 gram without battery
- MSRP: $160
- LED: Cree MT-G2 P0 (neutral white)
- ANSI FL-1 Output/Runtime: 2420 lumens (1hr 34min), 1900 lumens (2hr 3min), 1030 lumens (4hr 14min), 190 lumens (13hr 11min), 25 lumens (8 days), 2 lumens (42 days)
- 68,500 cd beam intensity / 523m beam distance
- Highly efficient circuit design offers maximum output and runtime
- Total length: 208.5mm / Light body diameter: 51mm / Light head diameter: 80mm
- Weight 680 gram without battery
- MSRP: $180
Packaging is distinctive for these Vostro BK-FA-series lights. Inside the hard cardboard box (with series overview on the back), you will find the light inside its well-fitting hoslter, spare o-ring, warranty card, manual, wrist lanyard (not shown above), and cloth bag with closing drawstring.
From left to right: Eagletac Protected 18650 3400mAh; Niwalker Vostro BK-FA02 (shipping), BK-FA02 (pre-release); L3 Illumination X40; Crelant 7G10.
All dimensions directly measured, and given with no batteries installed (unless indicated):
Niwalker BK-FA01 (shipping): Weight: 682.3g (864g with 4x18650), Length: 209mm, Width (bezel): 80.0mm, Width (tailcap): 50.3mm
Niwalker BK-FA01 (pre-release): Weight: 689g (873g with 4x18650), Length: 208mm, Width (bezel): 80.0mm, Width (tailcap): 51.9mm
Niwalker BK-FA02 (shipping): Weight: 687.6g (870g with 4x18650), Length: 209mm, Width (bezel): 80.0mm, Width (tailcap): 50.3mm
Niwalker BK-FA02 (pre-release): Weight: 689g (873g with 4x18650), Length: 208mm, Width (bezel): 80.0mm, Width (tailcap): 51.9mm
Crelant 7G10: Weight 643.4g (827g with 4x18650), Length: 198mm, Width (bezel): 79.0mm
Eagletac MX25L2 (standard head):Weight: 468.7g (with battery pack: 744.2g), Length: 266mm, Width (bezel): 62.0mm
Foursevens S18: Weight: 700g (800g with 6xCR123A), Length: 233mm, Width (bezel) 63.0mm
Fenix TK75: Weight: 516.0g (700g with 4x18650), Length: 184mm, Width (bezel): 87.5mm
Olight SR95: Weight: 1,224g (with battery pack), Length: 323mm, Width (bezel): 87mm
Thrunite TN31: Weight: 572g (est 724g with 3x18650), Length: 203mm, Width (bezel): 79.0mm, Width (tailcap): 49.0mm
Xtar S1 Production: Weight: 876.0g (est. 1028g with 3x18650 protected), Length: 240mm, Width (bezel): 83.4mm
The BK-FA-series has a substantial form factor, in keeping with other 3x and 4x18650 lights in this space. The final shipping versions have a few obvious (and not so obvious) updates, as explained below.
One change from the pre-release samples is the finish seems to have much thicker anodizing, and is even more matte. The closest comparable I've seen is from Armytek (although the Niwalkers are not quite that thick). There were no chips or damage on my samples (although one of the o-rings was a bit chewed up). Knurling pattern has changed from pre-release samples, but the thicker anodizing helps with grip (which is reasonable).
As before, both my samples came with serial numbers, and all lettering was bright white and clear against the dark background. The font used on the lights is particularly small.
One apparent difference is that the control rings have gotten a bit "taller" on the surface of the light, and are easier to turn now (i.e., can turn single-handed). There are still clear detents at all levels, and ring motion is smooth. There are also small labels showing the relative output mode of the light (although again, the font is small).
One thing that isn't as obvious is that it is harder to unscrew the body handle from the head now. There is less space to grip the head when turning - unless you grab the ring, which will change modes (i.e., turn to max when unscrewing, strobe when tightening). If you grab the head above the ring, you wind up unscrewing the bezel from the control ring area.
The lights can still tailstand stably, thanks to the flat base. But there are now cut-outs to allow a wrist lanyard to be attached. Niwalker forgot to send me one, but I understand these will be standard with the shipping lights.
Like before, screw threads are anodized and feature square-cut (trapezoidal) threads. However, I find the shipping versions can no longer be consistently locked out by a twist of the head, as the pre-release samples were able to. This seems to be due to the carrier re-design and/or the spring tension in the head.
There is a central contact point in the center of the head of the light, which has a spring underneath. This makes contact with the recessed inner positive terminal of the battery carrier. The negative current path is carried from the outside part of the battery carrier. Note that the carrier has been re-designed:
The original pre-release carrier has a solid feel, with thick all-metal end plates and sturdy struts. However, tension on the springs was low, and many cells felt "loose" inside the carrier.
The revised carrier has only a narrow band of connectivity around the end plates (which should reduce the risk of accidental shorting). Also, much longer and thicker springs are now used, making the tension on 18650s in the carrier much higher. In fact, this is now one of the "tightest" carriers I've seen for typical length 18650s. The struts are a bit thinner, so all thickness cells should now fit fine inside the light.
Like before, the carrier has a 2s2p arrangement (i.e., two cells in parallel, two channels in series). This means that you could run the light on just 2x18650 or 4xCR123A, but I wouldn't recommend this on the higher output modes (unless using IMR chemistry 18650s which can handle the higher current drain). Niwalker points out that 3x18650 or 6xCR123A could also be used, but I think this would be a bad idea, as you doubling the capacity of one channel only.
Also as before, the carriers are reversible – they fit and work in the light in either orientation.
The heads appear to be unchanged from the previous models (although I note the MT-G2 specs now specify the P0 output bin).
As before, both lights use a particularly large reflector – among the deepest I've seen, in fact. Overall dimensions and appearance are again very similar to the Thrunite TN31, but the BK-FA01 is actually slightly deeper. For an equivalent drive level, I would expect slightly better throw than the XM-L2 version of the TN31. For the BK-FA02, there's a slight difference in the opening at the base of the reflector, but overall dimensions seem otherwise comparable.
In both cases, the emitters were well centered in their reflectors. The XM-L2 emitter is probably already very familiar to the members here, but the MT-G2 is relatively new in the flashlight world (see the Cree MT-G2 spec sheet for more info.
As you can tell, the MT-G2 is a remarkably large emitter, with a dome diameter of almost 8.9mm (vs. 5mm on the XM-L2). Of course, what really matters is the surface area of the die underneath, which is only 2x2mm on the XM-L2. I am not sure of the actual die dimensions on the MT-G2, but as you will see in the blow-up pics below (same magnification), there appears to be a grid of 72 distinct segments.
Here are some close ups from my initial NWK1000 engineering samples:
The result of this will be reduced throw for a given output level, compared to even the relatively large Luminus SST-90. Note as well that the MT-G2 only comes in a variety of relatively neutral-warm tint bins (i.e., the coolest one available is 5000K). All the MT-G2 samples I've seen have certainly been in the typical "Neutral White" range.
The user interface has not changed from the pre-release samples (although there are now indicator labels on the control ring).
The BK-FA-series lights use a magnetic control ring very similar in function to the Thrnunite TN30/31. The rings do have pronounced detents at each position (i.e., you can feel when the light "locks" into position for a given mode), and you can now more easily change levels single-handed.
You turn on or change output modes by turning the control ring. Arranged from left-to-right (looking down at the light, held in traditional forward flashlight carry), the modes are: Strobe > Standby Off > Level 1 > Level 2 > Level 3 > Level 4 > Level 5 > Level 6 (max). See my testing results later in this review for the relative output mode spacing.
I've seen similar oritentations on small hand-held lights (i.e., Strobe being located to the left of Standby/Off). But most manufacturers tend to put any blinky modes at the end of the sequence, by the highest output.
No light is produced on Standby/Off, but a small current will be drawn to allow the circuit to respond to a ring turn (see below). As always, I recommend you store such lights locked-out by a head twist.
For more information on the overall build and user interface of the final shipping BK-FA-series, please see my video overview:
Videos were recorded in 720p, but YouTube typically defaults to 360p. Once the video is running, you can click on the configuration settings icon and select the higher 480p to 720p options. You can also run full-screen.
As with all my videos, I recommend you have annotations turned on. I commonly update the commentary with additional information or clarifications before publicly releasing the video.
The BK-FA01 and BK-FA02 show completely identical circuit patterns at all levels. The lights appear to use high-frequency PWM that is not visible to the eye (2.53 kHz), except for the highest level (which is constant). This is similar to the 2.45 kHz I measured on the pre-release samples.
However, it is a little more complicated than that. At the three lowest levels, the lights have a re-occurring signal at this 2.53 kHz frequency – but without the typical PWM pattern, as shown below for L2 and L3
As you can see above, you just get a simple spike at this frequency on these three lowest levels. The intensity of the signal seems directly proportional to the output level, and there is no sign of the classic PWM pattern (i.e., the on-phase should be getting longer as you go up in output). In contrast, the next two levels clearly show a typical PWM profile, at the same frequency:
Here you can see the typical PWM pattern – at Level 4, the light is on ~45% of the time, and level 5 the light is on ~80% of the time. This is exactly what you would expect, based on my estimated output measures (see later in the review).
Note that at Level 6, there is no signal at all – the light is at full uninterrupted power.
There is also a reoccurring signal pattern on the lower levels, but it doesn't cause any visual effect:
And finally, strobe:
Strobe is a consistent 10Hz in my testing, on both lights, as before.
Due to the electronic control ring, the BK-series lights will always be drawing a current when the body/carrier is connected to the head. On the shipping BK-FA01 I measured this current as 555uA (525uA on pre-release), and on the BK-FA02 I measured it as 520uA (similar on the pre-release).
Assuming 4x 2600mAh capacity batteries in the 2s2p arrangement (i.e., 5200mAh effective capacity), that would give you ~390-415 days for the lights (or just under 14 months). This is not unreasonable for this type of light, but I do recommend you store the lights with the head locked out when not in use. This just requires a quick turn from fully tight.
And now, what you have all been waiting for. All lights are on their standard battery, or AW protected 18650 2200mAh for the multi-18650 lights. Lights are about ~0.75 meter from a white wall (with the camera ~1.25 meters back from the wall). Automatic white balance on the camera, to minimize tint differences.
Note that in the beamshots below, the pre-release versions are not specifically labeled (i.e., the shipping versions are identified as "ship").
It's hard to see above, but the shipping BK-FA01 actually has slightly greater max output (and concurrent throw) than my pre-release sample (see my direct measures later in this review). As before, the BK-FA01 has a narrower spillbeam than most lights in the ultra-thrower category. It also has a more tightly focused hotspot that is smaller than any other light I've seen in this class (although there is a reasonable size corona around that hotspot).
Note that in the beamshots below, the pre-release versions are not specifically labeled (i.e., the shipping versions are identified as "ship").
Note: Again, don't be fooled by relative tint differences for the MT-G2s above – the automatic color balance used by the camera introduces distortions in tint. In real life, I find the shipping BK-FA02 sample slightly less warm than my pre-release sample (although both would be considered definite "Neutral White").
Again, there is a slight increase in max output on my shipping version of the BK-FA02 compared to the pre-release sample (although throw doesn't seem significantly different). The BK-FA02 has an identical spillbeam width as the BK-FA01, but the pattern of the beam is quite different, obviously. In keeping with the large emitter, you see a broad hotspot on the BK-FA02, and a "floodier" beam (i.e., the distinction between hotspot and spill is less great than the BK-FA01).. Clearly, the MT-G2 emitter is not designed for heavy throw applications.
For the rest of my indoor and outdoor beamshots below, these are based on the pre-release samples. When I get a chance to do additional shots, I will update this thread.
Here are some indoor shots, to allow you to compare the throw and spill of the three lights. For your reference, the back of the couch is about 7 feet away (~2.3m) from the opening of the light, and the far wall is about 18 feet away (~5.9m). Below I am showing a series of exposures, to allow you to better compare hotspot and spill.
As you can see above, the BK-FA01 has the most focused hotspot I've tested in this class. Not surprisingly, it is the current reflector-based leader in throw, among my collection.
The larger-die MT-G2 – coupled with the deep reflector of the BK-FA02 – gives a beam pattern very similar to the SST-90-equipped Eagletac MX25L2 (standard head). And again, beam tint above is not representational, due to auto-color correction. In real life, the BK-FA02 is a relative warm Neutral White (in comparison to the Cool White SST-90s).
For outdoor beamshots, these are all done in the style of my earlier 100-yard round-up review. Please see that thread for a discussion of the topography (i.e. the road dips in the distance, to better show you the corona in the mid-ground).
FYI, any "streaks" you see across the images are bug-trails. Flying insects are often attracted to the bright lights, and their flight trails get captured as swirly streaks due to the long exposure time. Also, ignore any tint differences below – they are mainly due to the automatic white balance setting on the camera.
Again, these shots below are based on the pre-release samples.
Obviously, the BK-FA02 has a lot more output than the BK-FA01 – but the BK-FA01 is far more focused for throw. To really put that in context, let's examine each relative to other lights in the same class, starting with the BK-FA01 (XM-L2):
As the wide-angle shots show, the BK-FA01 has a smaller hotspot than the Thrunite TN31 or Eagletac SX25L2 Turbo (i.e., more focused for throw). The close-up shots are a little misleading here, due to the smaller hotspot on the BK-FA01 - the close-up may seem dimmer (since it is restricted to just the hotspot/corona, and doesn't show all the light in the spill). Also, keep in the mind this is the pre-release version shown above.
And now the BK-FA02:
As you can see above, the main difference between the BK-FA02 and Crelant 7G10 is in the spillbeam width and intensity.
The BK-FA02 is a good comparable for multiple-emitter lights – but with a narrower and smoother spillbeam (i.e., free of artifacts). The BK-FA02 has greater throw than the Thrunite TN30, but not as great as the Fenix TK75.
UPDATE OCTOBER 6, 2013: FYI, I've just posted a review of the Crelant 7G5MT, so have done some additional outdoor beamshots. I think this batch looks fairly good, due to all the Fall colors in the trees.
As you can see, the BK-FA02 has more output than the competing Crelant MT-G2 lights, but with a narrower overall spillbeam. And note that this is the shipping version of the BK-FA02.
All my output numbers are relative for my home-made light box setup, as described on my flashlightreviews.ca website. You can directly compare all my relative output values from different reviews - i.e. an output value of "10" in one graph is the same as "10" in another. All runtimes are done under a cooling fan, except for any extended run Lo/Min modes (i.e. >12 hours) which are done without cooling.
I have devised a method for converting my lightbox relative output values (ROV) to estimated Lumens. See my How to convert Selfbuilt's Lightbox values to Lumens thread for more info.
Throw/Output Summary Chart:
My summary tables are reported in a manner consistent with the ANSI FL-1 standard for flashlight testing. Please see http://www.flashlightreviews.ca/FL1.htm for a discussion, and a description of all the terms used in these tables. Effective July 2012, I have updated all my Peak Intensity/Beam Distance measures with a NIST-certified Extech EA31 lightmeter (orange highlights).
As you can see above, there is a slight bump in max output on the shipping versions of the BK-FA01 and BK-FA02.
Starting with the BK-FA01, you may notice the apparent similarity in output to my XM-L-equipped Thrunite TN31. This is a little misleading, as my TN31 steps down after 3 mins whereas the BK-FA01 does not (see runtimes later in this review). Consistent with my indoor beam shots, the larger reflector on the BK-FA01 is giving this light an advantage over the TN31 (i.e., smaller and more focused hotspot). The 154,500 cd (lux @1m equivalent) makes the BK-FA01 an outstanding thrower (e.g., exceeds the regular SST-90-equipped Olight SR90 or SR95).
As for the MT-G2-equipped BK-FA02, overall output is now toward the high range of 3xXM-L and 1xLuminus SST-90-equipped lights. Throw is certainly acceptable for the class, and again within the typical range of 3xXM-L lights. Of course, one of the nice things about a single MT-G2 emitter is that you don't have the artifacts in the beam profile produced by multiple emitters.
With the shipping versions, I now have detailed specs to compare my estimated output measures:
In general terms, on the BK-FA01, the output levels L3-L6 increased by ~10-15% on my shipping sample, compared to the pre-release. In contrast, L1-L2 decreased in output by ~35-40%.
On the BK-FA02, only L6 increased significantly by ~10%. L1-L3 decreased by ~30-35%.
In absolute terms, it seems like the pre-release samples are more consistent with the Niwalker specs. That said, I find overall spacing to be pretty good on both models.
Given the interest on the MT-G2 model, let's see how the shipping version compares to the pre-release sample:
On both my standard AW protected 2200mA 18650s and more common 3100mAh cells, the max L6 level of the shipping version has a definite boost in output – with no change in runtime. There also seems to be a slight increase in runtime at the L5 level.
How do various type of cells compare at L6?
Primary CR123A perform well in this light. But again, if you are not planning on using the full 8x compliment of cells, I recommend you stick to low levels (i.e. L1-L4) only.
Let's see how the BK-FA01 and BK-FA02 shipping models compare to their respective competition:
As expected, performance is relatively similar to the Thrunite TN31 (but with more output and runtime, due to the fourth 18650 cell and XM-L2 U2 emitters). The main difference is that the BK-FA01 doesn't step down on L6 (max), and maintains its constant brightness for longer.
There's an interesting slow undulating pattern to the regulation on the BK-FA01 on L3-L5 (shown above), but this is impossible for you to notice by eye – for all intents and purposes, the light remains perfectly flat regulated in use, until the cells are nearly exhausted – at which point, the light steps down to L2. This is a thoughtful design, as it means you are never left accidentally in the dark, without plenty of warning first.
For the BK-FA02, the 18650 runtime pattern is different – although there is a brief period of quasi-reulated/slightly variable output in the first ~10 mins on L5 and L6, you typically see a direct-drive-like slow decay in output at all levels. Note that this is actually a very efficient means to control a light, and the reduction is gradual enough that you cannot notice it in practice. As before, when the batteries near exhaustion, the light drops to the L2 level (where it maintains flat regulation for a good amount of time before the cells are dead).
FYI, the effect of cooling introduce some differences in how quickly the initial quasi-regulated level last. Please see my earlier pre-release sample review for a discussion.
On 8xCR123A, you can see that the light maintains a relatively stable output for a long period of time, even at the max L6 level.
Due to the electronic control ring, the lights have a stand-by current when the head is fully connected to the body. I measured this at ~520~555uA across all my samples, which would translate into about 14 months for standard 2600mAh 18650 cells. While reasonably low, I recommend you store the lights locked out at the head when not in use (i.e., a simple quarter turn will break the current).
The control ring design has improved, facilitating grip and single-handed mode changing. However, due to the easier access to the emitter/reflector, it is much harder to unscrew the body handle from the head without turning the control ring instead.
While the BK-FA01 has tightly regulated performance at all levels, the BK-FA02 shows a largely direct-drive-like pattern at all levels on 18650. Note that direct-drive is actually more efficient, and both lights show a step-down to L2 before the batteries are exhausted. This means that you could safely use unprotected cells if you wanted, and will never be stranded without warning.
The lights use PWM at some levels – but at a non-visually detectable 2.45 kHz. I had noticed some audible hum on both my pre-release samples on L4 and L5, but both my shipping samples are hum-free.
Lights can roll easily on their sides.
The shipping versions can no longer be consistently locked out by a twist of the head, as the pre-release samples were able to. This seems to be due to the carrier re-design and/or the spring tension in the head.
The final shipping versions of the BK-FA01 and BK-FA02 both show a small bump in max output (compared to my previous pre-release samples), with otherwise similar performance. There have also been a number of build updates – please see the detailed pics, table and graphs in this new full review of the shipping versions.
Starting with the build, the main external differences of shipping versions are the larger control ring in the head (with smoother action and identifying labels now), and wrist lanyard attachment points in the tail. Anodizing has also been updated, and seems much thicker and "grippier" now. The lights remain very robust for this class.
There is no change to the reflectors that I can see – they continue to have extremely deep and smooth reflectors, for maximum possible throw. Inside, the battery carriers have been updated with reduced surface contact area on the plates (likely to reduce the risk of accidental shorting), and much stiffer individual well springs. On that note, there is no longer any risk of short cells not making proper contact – but tall cells will now be a struggle to insert/remove into the carrier.
The user interface is unchanged, and the control ring maintains clear detents (with even smoother action now, allowing single-handed use).
Circuit performance shows a nice bump in max output on both lights – with no real change to runtimes. Overall efficiency seems excellent for the class - despite the use of high-frequency (non-visible) PWM on all levels below max. The BK-FA01 remains one of the most flatly-regulated lights I've seen, while the BK-FA02 continues to use an efficient direct-drive-like pattern. As before, both lights show the clever adaptation that they step-down to the regulated Level 2 before the as the batteries near exhaustion. This means that you not will be stuck with an abrupt shut-off in typical usage – there is always plenty of warning.
In terms of throw, the BK-FA01 is definitely my XM-L2 class leader at the moment. Although I don't have the TN31 XM-L2 on hand to compare, I doubt it could beat it (based on the performance of my XM-L version). The larger reflector of the BK-series will likely give a consistent edge to this build, for equivalent drive level.
In the terms of the BK-FA02, this is probably going to be the best throwing light in the new MT-G2 class, thanks to the deep reflector. This novel emitter is quite large (i.e., it makes the Luminus SST-90 seem petite). Throw in this case is good, similar to the smaller non-Turbo head of the SST-90-equipped Eagletac MX25L2. Output is typically higher than most SST-90 light I've tested, and toward the higher end of typical 3xXM-L lights I've tested.
Of course, you get a much nice looking beam profile with the single MT-G2 emitter – a strong hotspot, with nice wide spill. I particularly like that the MT-G2 series only comes in range of warm-neutral tints. All my samples have been a pleasing neutral white to date.
Niwalker has done good job on the final release versions of these lights – as always, I commend them for taking the time to run multiple versions of engineering samples by me, for testing and feedback. The BK-FA01 and BK-FA02 are certainly good options to consider in their respective high-thrower/high-output classes.
BK-FA01 and BK-FA02 final shipping samples provided by Niwalker for review.